Apparatus for controlling the discharge of flowable material

ABSTRACT

An apparatus for controlling the discharge of flowable material from a first compartment having a discharge opening near a lower end thereof comprises a closure member which is movable by an actuator and an adjusting device between a closed position in which it shuts the discharge opening and a raised open position in which it opens a gap of a certain width to said discharge opening to allow the flowable material to flow through the gap and the discharge opening. Adjoining the discharge opening is a conveyor section for providing a predetermined path of conveying the material into a second compartment in communication with the conveyor. The quantity of material is determined by a quantity determining means flown to the second compartment. Furthermore, a control unit controls at least the adjusting device and the width of the gap to achieve a desired degree of filling and concentration within the second compartment.

FIELD OF THE INVENTION

[0001] This invention relates to an apparatus for controlling thedischarge of flowable material from a first compartment that has adischarge opening near a lower end thereof. A closure member is movablebetween a closed position in which it shuts this discharge opening and araised open position in which it opens an annular gap of a certain widtharound the discharge opening to allow said flowable material to flowthrough said gap and said discharge opening. There are conveying wallsadjoining the discharge opening for providing a predetermined path ofconveying the flowable material, when flowing through the dischargeopening, into a second compartment in communication with the conveyingpath. An actuating device moves the closure member from its closedposition into its open position and vice-versa. Furthermore, there is anadjusting device for adjusting the width of the above-mentioned annulargap. Support means in the path of the conveying walls hold both theactuating and the adjusting devices.

[0002] Such an apparatus is disclosed in U.S. Pat. No. 6,123,233. In anapparatus of this type, the flowable material is of a certain sensitiveor hazardous nature and may consist of powdery vitamins or alsodangerous dust, e.g. chemicals or even radioactive substances.Therefore, it is clear that the term of “compartment” should beconsidered in its widest sense and may encompass conveying vessels,bins, conveying conduits, mixers, reactors or process and reactionzones, e.g. in a chemical process. Accordingly, the term of “filling andconcentration degree”, as used below, has to be understood in itsbroadest meaning. Although U.S. Pat. No. 6,123,233 describes a specificand especially advantageous actuating device, the present invention isnot restricted to it, but could also use bellows, cylinders or otheractuators.

BACKGROUND OF THE INVENTION

[0003] Although the known apparatus is quite suitable for metering theflowable material form the first compartment into the second compartmentwhich is often selectively coupled or docked to the first compartment,the requirements regarding the accuracy of dosing a predeterminedquantity become higher and higher. This is clearly in connection withthe special type of material thus handled. The known device, althoughbeing provided with an adjustment device, was only able to effect dosingrelative roughly—as compared with the requirements of today. One reasonis that the flowing properties of the bulk material are dependent on thefilling level within the first compartment and, thus, vary over timewhen the material flows out.

[0004] From DE-A-29 23 444, WO 90/08724 and U.S. Pat. No. 4,691,843, itis known to vary the gap of the closure member by varying its open topposition. However, all these known designs are constructed in such a waythat, in order to vary this gap, a fitter had to have access into theinterior of the bin or vessel. This is, of course, not possible whilethe material flows out. Thus, the operation of the bin or vessel had tobe interrupted, and the latter had to be dismantled so that the fittercould reach the interior. It is clear, that it could even be dangerousfor the man to contact there the hazardous substances. When the fitteris in the interior, he cannot check the effect of his adjustment ontothe flow properties of the material and, therefore, adjustment can onlybe effected very roughly and arbitrarily, and one can only determinewhether the adjustment was correct or insufficient during operation. Inaddition, bulk material in a vessel may assume a different consistencyover time. The result may be that the adjustment and position chosen isfirst suitable, but leads to varying flow properties over time in one orthe other sense. However, varying the position of the closure memberduring operation is not possible with the known designs.

SUMMARY OF THE INVENTION

[0005] Therefore, it is an object of the present invention to enable or,at least, facilitate precise fine metering without the necessity ofinterrupting the operation.

[0006] This object is achieved by providing a quantity determiningdevice for determining the amount of flowable material flown to thesecond compartment, and a control arrangement for controlling at leastthe adjusting means and the width of said gap to achieve a desireddegree of filling and concentration within the second compartment.Although it is preferred to have the control effected automatically byconnecting the quantity determining device to the control arrangement,this is hot necessary under all circumstances; for example, it could besufficient that the quantity determining device merely indicates theamount of flowable material flown to the second compartment or degree offilling and concentration by measuring a related value so that anoperator can accordingly handle the control arrangement. The amount offlowable material flown to the second compartment can be determinedeither more or less directly by weighing or measuring the volume, orindirectly by determining the concentration of the material in a processzone, e.g. by measuring the pH or an increase (or decrease) intemperature caused by the material in the zone, by using a Geigerdetector or the like.

[0007] The use of an actuator of variable gap is, in principle, knownfrom the above-mentioned DE-A-29 23 444, WO 90/08724 and U.S. Pat. No.4,691,843. To add an adjustment device to an invariable actuator isknown per se by U.S. Pat. No. 6,123,233. However, to combine them with acontrol which is able of controlling the adjustment device duringoperation, i.e. during filling, in such a manner that the flow offlowable material can be controlled by selecting the width of thedischarge gap is the “missing link” which enables precise dosing andmetering.

[0008] In principle, it would be conceivable to have the controlarrangement acting onto both the actuator and the adjustment device, forexample in the sense of a cascade control wherein the adjustment deviceis controlled into an extreme position and the actuator is used forsetting the desired gap width (or vice-versa, the actuator moves into apredetermined position, while the adjustment device adjusts the gapwidth which is preferred).

[0009] Particularly in the case of a vertical arrangement, e.g. asaccording to U.S. Pat. No. 6,123,233, the construction according to theinvention also be used for loosening the bulk material in the firstcompartment by raising and lowering the actuator relative quickly, thusachieving the effect of a vibrator, i.e. promoting flow of the material.In this way, a separate vibrator can be omitted. This can be doneautomatically, if desired, if the control arrangement is formed tocontrol also the loosening device. Such loosening device can also beformed, as is known per se, be air nozzles in the region of the top ofthe closure member, i.e. on it or around it.

[0010] In any case, the quantity determining device for determining theactual degree of filling and (or) concentration, e.g. in a second vesseldocked to the conveying path of the first vessel, in the case of amanual operation, it is possible to read the indication of the degreeand to close the closure member, when a desired degree has been reached.

[0011] However, it is also possible to chose a wider discharge gap if itturns out that the gap width normally used leads to too long a fillingtime. To this end, it is useful-if the quantity determining devicecomprises a timer for determining the degree per time unit.

[0012] All these functions cane be automated, if the control arrangementcomprises a comparator stage for comparing the degree preset by apresetting device with a value related to the actual degree determinedby the quantity determining device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Further details of the invention will become apparent from thefollowing description of embodiments schematically represented in thedrawings in which

[0014]FIG. 1 shows an embodiment comprising a variable actuator as isknown by the prior art, but which has a balance for determining thefilling degree and a control arrangement, which embodiment issupplemented, according to the invention and

[0015]FIG. 2 by an adjustment device in conjunction with the actuator,the amount of material flown to a second compartment being determinedvolumetrically.

DETAILED DESCRIPTION OF THE DRAWINGS

[0016] According to FIG. 1, bulk material (or even liquid material)should be transferred from a bin 1 or any other compartment through adischarge hopper 2 and a discharge opening 3 at the lower end of the bin1 and into a funnel-shaped conveying section 4 and a container 5 dockedto it. The size ratio of bin 1 and container 5 are only roughlyrepresented, i.e. the bin or discharge vessel 1, which is shown to berelative large could be smaller in relation to the container 5, and thelatter may be larger than illustrated in FIG. 1. Although the inventionwill subsequently be described with reference to a purely vertical flowof material, it is also known that such bins 1 may have their dischargeend turned to the side. Furthermore, the docking devices are not shownand may assume any shape known per se, since it is not of anysignificance for the present invention. In FIG. 1, the conveying section4 and its conveying path comprises a discharge funnel 6 having anadjoining cylindrical portion 7 onto which the inlet opening of thecontainer 5 is slid on and is sealed, for example, by a bellows 8.Docking devices and corresponding sealings have been suggested invarious forms so that those skilled in the art may chose from a widefield of possibilities. As mentioned above, the container 5 is a mereexample of a variety of possible second compartments, for exampledifferent reaction zones of a single reactor or also of a mixer to befilled through a corresponding connection.

[0017] The discharge opening 3 may be closed, as known per se, by a cone31. This does not means that the present invention is restricted to thistype of closure members, although this type (or a frusto-conical one) ispreferred. However, it would also be possible to use a slide or rotaryvalve having either a horizontal or vertical axis of rotation, as hasalso been suggested for closing bins or other large containers.

[0018] Within the conveying section 4, an actuating device 15 for theclosure cone 31 is fastened and held by radial stretchers 9.Alternatively, the actuating device 15 could be held from inside thebin, as is also known per se, but not preferred. The actuating device 15comprises an actuator cone 10 which, in raised position, engages theclosure cone 31 from below and then raises the cone 31 so that anannular gap is formed around the edge of the closure cone 31 and isdefined exteriorly by the discharge hopper 2, when the actuator cone 10is completely raised to its maximum height. Bulk material will then flowthrough this annular gap, through the conveying section 4 and into thedischarge funnel 6 and finally into the container 5.

[0019] In order to promote this flow and transfer of material, avibrator 11, forming part of the actuating device 15, is often (but notalways) provided below the actuator cone 10 and is, for example,pneumatically actuable. The supply of actuating air can be effectedeither through a pneumatic conduit 12 shown or via a separate conduit.

[0020] For this conduit 12 leads, as represented, to an actuationcylinder 13 whose piston rod 14 is connected to the actuator cone 10and/or the vibrator 11 at top. The details of this connection are ofknown nature and should, therefore, not be discussed in detail. However,it should be noted that the piston rod 14 may cooperate with a magnetic(or other) sensor 16 which is attached to the cylinder 13. As isindicated in dotted lines, the piston rod 14 is provided with a threadbelow a tube that is slid over. This thread constitutes a magneticdiscontinuity in accordance with U.S. Pat. No. 3,956,973. When thepiston rod 14, starting from its initial position corresponding to theclosed position of the cone 31, is displaced in upward direction, eachof these discontinuities causes a pulse from the sensor 16 to bedelivered to a line 17 so that the position of the piston rod can bedetermined at any time by counting the pulses. Since finally the cone 31is raised via the piston rod 14, the position of the cone 31 may bedetermined in this way and, thus, the width of the annular gap betweenthe cone 31 and the discharge hopper 2.

[0021] Counting the pulses, i.e. determining the position of the cone 31and the width of the annular gap between the peripheral edge of the cone31 and the discharge hopper 2, is effected by means of a control unit orprocessor 18, preferably a micro-processor, which receives, at the sametime, an information relating to the degree of filling from thecontainer 5, here in terms of weight. To this end, the container 5 isformed, according to the present embodiment of FIG. 1, as a weighingcontainer, i.e. it is supported by load cells 19 schematically indicatedor is provided with similar sensors for determining the weight. Thesesensors 19 will supply an information about the actual filling degree ofthe container 5 to the processor 18. In the case of measuring aconcentration in an, e.g. chemical, process, a wide variety of sensorsfor determining the concentration could be used, such as viscometers, pHprobes, nephelometers, spectrometers, gas meters (e.g. for measuring theconcentration of gas derived from a substance delivered from bin 1),such as CO₂ meters, oxygen meters and so on. In the case a mixer is usedas a second compartment, it would be possible, for example, to determinethe concentration of bulk material in a blend by measuring the currentconsumption of the mixer motor. Alternatively, when electricallyconductive material has to blended, such as graphite dust or metal dust,the conductivity of the blend could be measured.

[0022] In this way, the container 5 could be formed and used as a premixcontainer which picks up a desired quantity of each one of individualcomponents from different bins 1 to comply with a given formulation. Thebalance 19 determines the weight of the container 5 at arrival at acertain bin after which the necessary amount of flowable material fromthe next bin or vessel to which the container 5 is docked is added. Ofcourse, it would be possible to do without the information relating tothe actual position of the cone 31, that is supplied via the line 17,because it may be sufficient to know from the signals of the sensors 19that the container 5 has not yet received the necessary quantity offlowable material. It should be noted that in some applications, as analternative or cumulatively, the loss of weight of the bin 1 (or otherfirst compartment) could be determined, e.g. instead of determining theincrease in weight of the container 5 (or a second compartment).

[0023] In order to automate the operation, it is preferred to connect anoperating panel 20,to the processor 18 which displays the fillingquantity within the container 5 by a display 21, on the one hand, and ispreferably provided with an input key board 22 in order to preset thedesired (nominal) quantity of flowable material or the desired fillingdegree of the container 5. The processor 18 may have a comparator stage23 for comparing a value representative for the actual filling degree inthe container 5 with a preset desired filling degree. However, it wouldalso be possible to compare the actual filling degree with the positionof the cone 31, i.e. if the filling degree is unsatisfactory and theactual position of the cone 31 permits further opening, the annular gapbetween the peripheral edge of the cone 31 and the discharge hopper 2could be widened. Moreover, the processor 18 could comprise a furtheroutput line 11′ leading to a vibrator 11 in order to promote the flow ofmaterial from the bin 1 by vibrating it.

[0024] The adjustment of the height of the cone 31 is effected through asignal line 31′ which actuates a valve 24. In the closed position of thecone 31, as shown, the path from a source of pressurized air 25 to thepneumatic conduit 12 is interrupted. In a position 24′ of the valve 24,the source of pressurized air 25 communicates with the pneumatic conduit12 and supplies air under pressure to the cylinder 13 until the sensor16 indicates that a certain position given by the control unit 18 hasbeen reached. Then, the valve 24 is closed again and blocks, thus, alsodraining from the conduit 12, i.e. the respective position of the pistonrod 14 is fixed. If one wants to lower the cone 31 again, the valve 24is switched into the position 24″ in which the pneumatic conduit 12communicates with an air evacuation duct 26. It is clear that the outputline 11′ of the processor 18 is switched in a similar manner and thateither the line 11′ can be provided for controlling the vibrator 11,which forms part of the actuating device 15, or a line 31′ or both.Furthermore, it is to be understood that a vibrator may be also arrangedon the housing of the bin 1 or at any other place, instead of thevibrator 11 centrally arranged along the longitudinal axis of theactuating device 15. Alternatively, air is blown through nozzles intothe bulk material for loosening it, as is well known in the prior art.Actuating these air nozzles can also be controlled by the processor,either as an alternative or in combination with the other features. Inthis sense, the term of “actuating device” has to be understood in thebroadest sense as any actuating device which enables or facilitatesflowing of the material from the first compartment 1.

[0025] Providing at least two output lines 11′ and 31′ of the processor18 enables programming for cascade or sequential control. To this end,the cone 31 is displaced, for example, in one of its (variable) openpositions. If the increase of the filling degree of the container 5 isinsufficient, the vibrator 11 may be activated in a first step via theline 11′. If this does not lead to a satisfying result, the programcould be formed in such a manner that the cone 31 is raised further.This may be repeated until the flow of material or the filling degree inthe container is satisfying. Of course, the program could also bemodified by first opening the cone 31 further, if the flow of materialis insufficient, and activating the vibrator (or any other looseningdevice) only then if necessary. Nevertheless, loosening the flowablematerial can also be done according to the invention without anyvibrator 11, for example by using the control unit 18 to impress avibration movement to the cone 31 via the cylinder 13. It will beunderstood that the program of such a sequence has to be contained in aprogram memory that, for example, is incorporated as a memory 18a withinthe processor 18. However, it is preferred to have the program memoryreleasable connected to the processor 18 in order to be able to changethe program, if desired, and to adapt it to different requirements. Forexample, it would be conceivable for relative small quantities to bedosed to keep the actuating device 15 for the cone 31 in the positionwhich corresponds to the closed position of the cone 31, but to lift thecone 31 only slightly via the motor 28 (FIG. 2), in which case it may besuitable to provide either a position sensor (of similar function asthat of the sensor 16 of FIG. 1) for the position either of the cone 31or the spindle 29. To this end, the spindle 29 could be provided withan, e.g. optical, magnetical, capacitive or inductive, angletransmitter, or the motor 28 is formed as a stepping motor whoserevolving steps can be counted.

[0026] A further possibility is the following: Filling the container 5should be carried out in a time saving manner. FIG. 2 shows a means howfilling can be accelerated. Referring back, however, to FIG. 1, it isclear that a processor, such as processor 18, needs a clock generator 27for determining the course of a program anyway. This clock generator 27may serve as a timer for determining the variation of the filling degreeof the container 5 per time unit (the first derivation of the fillingdegree over time, i.e. the control unit 18 has to be able todifferentiate). In this way, controlling operation, as described above,could be effected in dependence on the filling rate or the fillingdegree per time unit. It will be understood that any other controlsystem with a clock generator 27 assigned as a timer could be usedinstead of a processor 18 provided with the clock generator 27.Reference has already been made above to FIG. 2. In this embodiment anactuation unit 15′ comprises two different devices, one of which, e.g.in the form of a bellows 13′, being for roughly actuating the cone 31,while the other one constitutes a fine adjustment device 15″ which, forexample, is designed in the manner described in U.S. Pat. No. 6,123,233.This arrangement can be used to reduce the time of filling by firstraising the cone 31 by means of the bellows 13′ to its maximum height sothat the bulk material flows down at a high rate, e.g. into thecontainer 5 according to FIG. 1. When the filling degree in thecontainer 5 reaches a (threshold) value near that nominal value presetby means of the key board 22, a motor 28 (be it an electrical motor or apneumatical rotating motor) can switched on to displace a threadedspindle 29 in such a way that the discharge gap of the bin 1 (beingpresent in FIG. 2 in the same way as in FIG. 1) is made smaller so thatdosing is effected in a highly precise manner.

[0027] Also in this case, a sequential control is possible. One couldprovide that first the cone 31 is lowered by the bellows 31′ when thefilling degree passes a first threshold value so as to reduce theannular gap between the peripheral edges of the cone 31 and the hopper 2(FIG. 1). At the same time, the motor 28 could rotate the threadedspindle 29 in such a way that a support plate 30, which engage itsthread, together with the actuator cone 10 reaches its relative maximumheight. Only when reaching another threshold value, the bellows 13′ (orother actuator) is, for example, lowered so that the cone 31 would closethe discharge opening 3, if the threaded spindle had not rotated so thata small annular gap remains still open for allowing the bulk material toflow through. Only when the nominal filling degree has been reached, thespindle 29 is rotated in the sense of completely lowering the cone 31into its closed position.

[0028] It is clear that the output line 28′ shown in FIG. 2 is purelyschematically illustrated; for in the case of a pneumatic motor, itwould be suitable to interpose an electrical motor control stage in theline 28′.

[0029]FIG. 2 shows also that the invention could likewise be applied tocontrol the filling degree in a volumetric manner. To this end, a rotaryvalve 32 may communicate with the conveying section 4 and may be drivenby a motor M. Of course, the filling degree of the individual cells ofthe rotary valve 32 will depend on whether a sufficient quantity of bulkmaterial flows out of the discharge opening (3 in FIG. 1). If it ispossible to determine the filling degree of the individual cells of therotary valve 32, a corresponding signal could be supplied to theprocessor 18′. Since, however, this could be difficult or unpreciseunder certain circumstances, it is possible to proceed as follows.

[0030] In the embodiment of FIG. 2, a pneumatic conveying conduit 33,e.g. operated under flight conveyance conditions, but optionally underconveyance conditions (slow conveyance), is postponed after the rotaryvalve 32. This conduit 33 leads to a container 5′ to be filled whichcommunicates with a separator 34, e.g. in the form of a cyclone. Thus, acertain level N within the container 5′ will result after a certaintime. This level N can be determined by a level meter or volumeter 19′,for example formed by an ultrasonic range detector or by any other knownvolumetric sensor. The result is supplied to the processor 18′ which, inturn, either via an output line 13″ controlling the bellows 13′, via theline 28′ which controls the adjusting device 28, 29 and/or via a line11′ (in FIG. 2 not shown for the sake of simplicity) actuates theloosening device (vibrator 11) in the manner described above.

[0031] It is certainly not necessary to provide a rotary valve 32. If,for example, the conveying conduit 33 is formed as a suction conduit, itwould be able to suck the flowable material immediately through theannual gap formed around the opened cone 31. Likewise, it is possible todesign the bin 1 as a pressure tank which presses the flowable materialthrough the annular gap. Even combinations of both procedures arepossible. However, in the case a charging valve is interposed, it mustnot necessarily be a rotary valve, but can be of any known nature.

[0032] It is clear that the rotary valve or its motor M could also beconnected to and controlled by the processor 18′ in order to give aninformation about the rotary speed and/or the number of revolutions(which, in turn, gives an information about the volume of materialconveyed). It is also conceivable to control the rotary valve 32 by theprocessor 18′ in such a manner that it conveys first at a large rate ofvolume of flowable material to the container 5′ and is then slowed downwhen the nominal filling degree is approached.

[0033] Thus, it may be understood by those skilled in the art that theinvention can be realized by a variety of different embodiments whichare not restricted to those illustrated in the drawings. Above all, itis possible to combine individual components or functions of theembodiments shown, for example by providing a balance 18 forgravimetrically dosing instead of a volumetrical one also in the case ofFIG. 2 and vice-versa. Furthermore, details of the control arrangementof one figure could be-applied to the design of the other figure. Forexample, actuation could be effected by motors, cylinders or bellows,and the closure member could also be modified. Instead of having aloosening device, a vibrator could be used for compacting the materialintentionally, because some bulk materials, such as metal dust, can bepromoted to flow by slightly compacting it (e.g. by a suitably placedvibrator).

What is claimed is:
 1. An apparatus for controlling the discharge offlowable material from a first compartment having a discharge openingnear a lower end thereof, comprising: closure means movable between aclosed position in which it shuts said discharge opening and a raisedopen position in which it opens a gap of a certain width to saiddischarge opening to allow said flowable material to flow through saidgap and said discharge opening, conveying means adjoining said dischargeopening for providing a predetermined path of conveying said flowablematerial, when flowing through said discharge opening, into a secondcompartment being in communication with said conveying means; actuatingmeans for moving said closure means from said closed position to saidopen position and vice-versa; adjusting means for,adjusting said widthof said annular gap; support means for holding said actuating and saidadjusting means; quantity determining means for determining the amountof flowable material flown to said second compartment; and control meansfor controlling at least said adjusting means and the width of said gapto achieve a desired degree of filling and concentration within saidsecond compartment.
 2. Apparatus as claimed in claim 1, wherein saidsupport means are arranged in the path of said conveying means. 3.Apparatus as claimed in claim 1, further comprising preset means forpresetting said desired degree of filling and concentration. 4.Apparatus as claimed in claim 3, wherein said control means comprisecomparison means for comparing the degree preset by said presettingmeans with a value related to the actual degree determined by saidquantity determining means.
 5. Apparatus as claimed in claim 1, whereinsaid quantity determining means comprise weighing means.
 6. Apparatus asclaimed in claim 1, wherein said quantity determining means comprisetiming means for determining said degree per time unit.
 7. Apparatus asclaimed in claim 1, wherein said adjusting means are adapted to varysaid width continuously.
 8. Apparatus as claimed in claim 1, whereinsaid closure means is conical at least in part.
 9. Apparatus as claimedin claim 1, wherein said closure means is vertically movable by saidactuating means and said adjusting means.
 10. Apparatus as claimed inclaim 1, wherein said control means comprise detecting means fordetermining the position of said closure means.
 11. An apparatus forcontrolling the discharge of flowable material from a first compartmenthaving a discharge opening near a lower end thereof, comprising: closuremeans movable between a closed position in which it shuts said dischargeopening and a raised open position in which it opens an annular gap of acertain width around said discharge opening to allow said flowablematerial to flow through said gap and said discharge opening, conveyingmeans adjoining said discharge opening for providing a predeterminedpath of conveying said flowable material, when flowing through saiddischarge opening, into a second compartment being in communication withsaid conveying means actuating means for moving said closure means fromsaid closed position to said open position and vice-versa; adjustingmeans for adjusting said width of said annular gap support means forholding said actuating and said adjusting means; quantity determiningmeans for determining the amount of flowable material flown to saidsecond compartment; and control means for controlling at least saidadjusting means and the width of said gap to achieve a desired degree offilling and concentration within said second compartment, said controlmeans comprising programming means for varying the width of said gapduring the flow of said flowable material.
 12. Apparatus as claimed inclaim 11, wherein said programming means are programmed to allow saidclosure means in a first step to form the annular gap so as to have amaximum width until a predetermined threshold value of said filling andconcentration degree is attained, and then to form a smaller gap. 13.Apparatus as claimed in claim 11, wherein said programming means arereleasably connected to said control means.
 14. Apparatus as claimed inclaim 1, wherein said control means are adapted to control also saidactuating means.
 15. Apparatus as claimed in claim 1, further comprisingloosening means for loosening said flowable material in said firstcompartment.
 16. Apparatus as claimed in claim 15, wherein said controlmeans are adapted to control also said loosening means.
 17. An apparatusfor controlling the discharge of flowable material from a firstcompartment having a discharge opening near a lower end thereof,comprising: closure means movable between a closed position in which itshuts said discharge opening. and a raised open position in which itopens a gap of a certain width to said discharge opening to allow saidflowable material to flow through said gap and said discharge opening,conveying means adjoining said discharge opening for providing apredetermined path of conveying said flowable material, when flowingthrough said discharge opening, into a second compartment being incommunication with said conveying means; actuating means for moving saidclosure means from said closed position to said open position andvice-versa; adjusting means for adjusting said width of said annulargap; support means for holding said actuating and said adjusting means;quantity determining means for determining the amount of flowablematerial flown to said second compartment; and control means connectedto said quantity determining means for controlling at least saidadjusting means and the width of said gap to achieve a desired degree offilling and concentration within said second compartment.